1. Field of the Invention
The present invention relates to robotic end effectors, and more particularly, to a relatively small, lightweight, end effector having a pair of hollow gripping fingers which are suitable for engaging, retaining and releasing a plurality of tools and components.
2. Discussion of the Relevant Art
The art abounds with end effectors utilized in combination with robots to perform a plurality of operations in automatic production lines. Numerous types of end effectors, each designed for a specific function, are in use today. The automatic production lines require numerous robots each performing their function in sequence so that the item being manufactured moves through numerous stations, each station adding a component or performing an operation on the article being manufactured until the article reaches the end of the production line where it is then tested and packaged for shipment.
In order to improve the versatility of the end effectors numerous designs have been attempted which have as a design goal providing three degrees of freedom to the end effector and robotic arm combination permitting manipulation similar to that accomplished by a human arm and hand. Typical of an end effector having force sensors in each finger together with a system providing three degrees of freedom force sensors on each finger utilizing strain gages to measure forces on the fingers as it contacts an article is disclosed in U.S. Pat. No. 4,132,318 issued to S.S. Wang, et al on Jan. 2, 1979. The device disclosed therein is capable of measuring the gripping force and a force vector applied to the object being held by a manipulator finger of the end effector. The end effector disclosed therein is computer controlled and utilizes the strain gages and offset forces to direct the fingers of the end effector to accomplish the desired goal. The type of functions that can be performed with this type of end effector are limited.
In U.S. Pat. No. 3,905,632 issued to H. J. Caylor, et al on Sept. 16, 1975 a gripping head apparatus is disclosed that is designed to be attached to the free end of a lifting boom structure which is configured to grip, position, empty and release containers wherein the head comprises a pair of movably mounted lifting arms arranged in opposed alignment in relation to one another. A rack and pinion arrangement is used to rotate the position of the container once it is picked up by the end effector. The device disclosed herein is utilized for the singular purpose of raising a container, moving it to a new position and then tilting it so the contents thereof can be emptied. The apparatus is designed for use with relatively large containers and would be unsuitable for handling the manipulated of small devices or performing specific functions on relatively small components.
Another mechanism utilized as an end effector on a robotic arm suitable for gripping rigid products is disclosed in U.S. Pat. No. 3,655,232 issued to G. A. Martelee on Apr. 11, 1972. The embodiment disclosed therein utilizes a horizontal ram and from which are suspended hollow vertical telescoping grasping arms each housing a vertical cylindrical ram connected to a compressed oil accumulator that supplies oil to the horizontal ram and to a rotating ram about the vertical suspension pivot. Here again, the device utilizes rack and pinion arrangements which are not suitable for the manipulative functions of which the instant invention is capable.
The apparatus disclosed in the instant invention overcomes the shortcomings found in the prior art by providing an end effector suitable for use on the distal end of a robotic arm capable of performing numerous functions and is capable of engaging and releasing numerous tool elements to aid in performing a plurality of functions while maintaining its small size and weight.
Therefore, it is the object of the present invention to provide a robotic end effector that is relatively small in size, reliable and suitable for performing numerous functions.
It is yet another object of the present invention to provide a robotic end effector suitable for mounting on a plurality of robotic arms.
It is still yet another object of the present invention to provide a robotic end effector that is small in size and provides a relatively large gripper dimension.
It is still yet another object of the present invention to provide a robotic end effector that is capable of bi-directional linear motion suitable for engaging the outer dimension of objects in addition to the inner dimension thereof.
It is still yet another object of the present invention to provide a robotic end effector suitable of engaging and exchanging numerous tool elements.
It is still yet another object of the present invention to provide a robotic end effector that is capable of automatically changing and replacing tool elements and is capable of performing numerous functions.
It is still yet another object of the present invention to provide a robotic end effector capable of sensing when the object it is to engage is in the correct position for engagement thereof.
It is still yet another object of the present invention to provide a sensing arrangement for the robotic end effector providing information to the control computer for the robot that the end effector has not encountered an object in its path and/or has moved to a prescribed position and is ready to perform it function.